This cleans up the ci scripts so that they can be run from an arbitrary directory, and so that they don't have any bash lint issues, and are more explicit about which dart/pub/dartanalyzer executable they run.
I also fixed the format script to take a "--fix" argument that will fix all of the formatting issues found, including trailing whitespace and gn files.
I added a warning to the license script about untracked/ignored files in the fluttter repo because those so often trip up the license script.
I added missing license information to the ci scripts too.
There's now a bit of boilerplate at the beginning of each script (the follow_links function) in order to reliably find the actual location of the script: I'd put it into a common file, except that that code would be needed to reliably find the common location too, so I needed to duplicate it. It's the same boilerplate as what is used in the flutter/flutter repo for the flutter and dart scripts.
I deleted the ci/test.sh script, since it seems to be obsolete (the test it tries to run doesn't exist anywhere).
* Roll dart to aece1c1e92.
Changes since last roll:
```
aece1c1e92 Update compile_flutter.sh after vm -> frontend_server rename
9293e26fc9 [gardening] Fix flutter hhh patch.
13fbf569f6 [flutter] split frontend_server from vm package
a389015083 Rewrite MethodInvocation to FunctionExpressionInvocation when the target is not a method.
ae251757a9 [vm,aot,bytecode] Performance fixes
01ebf92dde [VM] Consume extension member/is late flag setting when reading kernel file.
8e05cd278c [vm, bytecode] Emit bytecode without ASTs by default.
4539536b34 [eventhandler] generalize socket initialization
7115687beb NNBD i13n: Add a description for discarding just the condition
2bcaf02582 (origin/base) Update dartdoc to 0.28.7.
a0e8c7712d [dart2js] New RTI: Prevent elision of precomputed1 and remove unneeded read.
c38e19cbbe [vm/compiler] bit utilities
f918214f36 Add a unit test reproducing issue #38352.
ad47b1ca64 Remove summary1, part 2.
0881a4a691 Reland "Deprecate TypeParameterTypeImpl.getTypes()"
d93a6b596b Prepare to publish analyzer version 0.38.5
d5feab0c53 [vm] Create builds for LeakSanitizer, MemorySanitizer and ThreadSanitizer.
8c5236f55e [vm/ffi] Fix host-target word mismatch breaking AOT callbacks in ARM_X64.
5f7b837195 Remove unused FunctionElementImpl_forLUB.
2c75771611 Write and read the static type of IntegerLiteral.
b00453c68a Create synthetic FunctionType in quick fixes.
897e197dd4 Flow analysis: Update AssignedVariablesVisitor to track functions/methods.
55466fd3cc Flow analysis: Remove AssignedVariables.capturedAnywhere.
0a5cf36f14 Make exitFunctionBody safer.
```
* Update license hash
This reverts commit 651c90409ee7b8f43da7d1c60fcb172f1ad51901.
With this change applied, test/widgets/widget_inspector_test.dart is failing
when run by the dev/bots/test.dart script in the framework tree.
This improves performance as the version in the SDK is able to work more
incrementally and avoids creating an expensive ClassHierarchy.
There is now no measureable performance difference with the option so the
kernel transformer can be enabled by default.
