* 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