supplementErrorMessage should swallow TypeError

[scabug]

I just saw a case in which an abort due to:

[warn] creating stub symbol to defer error: bad symbolic reference. A signature in TraceMonitor.class refers to term actors
[warn] in package scala which is not available.
[warn] It may be completely missing from the current classpath, or the version on
[warn] the classpath might be incompatible with the version used when compiling TraceMonitor.class.

triggered a cyclic reference error in supplement error message, which is not caught by case _: Exception, and consequently obscured the original error.

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-7360?orig=1
Reporter: @retronym
Affected Versions: 2.10.0

[scabug]

@retronym said:
scala/scala#2389