Rename explicitOuter to explicitOuterPhase in Phases
Remove appliedIfMethod use ensureApplied instead
move caseAccessors from TypeUtils

They are in SymUtils
Adaptations to make pattern matcher in new world

Tests now always include erasure (before quite a few tests failed when erasure
was enableed). By contrast lazy vals creates problems with erasure, disabled
for now.

Some other small polishings on integration of pattern matcher with rest of dotc.

Deep recompilation of tools still fails, currently disabled.