This commit gets ready for the introduction of ngtsc template
type-checking tests by refactoring test environment setup into a
custom helper. This helper will simplify the authoring of future
ngtsc tests.
Ngtsc tests previously returned a numeric error code (a la ngtsc's CLI
interface) if any TypeScript errors occurred. The helper has the
ability to run ngtsc and return the actual array of ts.Diagnostics, which
greatly increases the ability to write clean tests.
PR Close#26203
This commit adds a new compiler pipeline that isn't dependent on global
analysis, referred to as 'ngtsc'. This new compiler is accessed by
running ngc with "enableIvy" set to "ngtsc". It reuses the same initialization
logic but creates a new implementation of Program which does not perform the
global-level analysis that AngularCompilerProgram does. It will be the
foundation for the production Ivy compiler.
PR Close#23455