[parser] Mark a few methods for inlining

Some recent changes to the parser looked like they should have cost
basically nothing but ended up costing a little bit anyway.
This CL marks the new functions for inlining recovering at least some of
the cost.

Change-Id: I599d557eb25bee892c8975d794618e837fec0caa
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/510320
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>

pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart

@@ -6934,6 +6934,7 @@ class Parser {
     return _parseExpression(token, /* allowCascades = */ false);
   }
 
+  @pragma("vm:prefer-inline")
   Token _parseExpression(Token token, bool allowCascades) {
     if (isPatternsFeatureEnabled && looksLikeOuterPatternEquals(token)) {
       return allowCascades
@@ -7454,6 +7455,7 @@ class Parser {
     return token;
   }
 
+  @pragma("vm:prefer-inline")
   ConstantPatternContext _reportInvalidConstantPatternOperator(
     ConstantPatternContext constantPatternContext,
     int precedence,