JVM profiler rejects traces dirs whose path contains a dot, so tests fail in dotted checkouts #6455

Problem

JavaContinuousProfiler (sentry-async-profiler) refuses any profiling traces directory whose path contains one of 26 characters, . among them. That has two effects:

• Tests: JavaContinuousProfilerTest's fixture uses a relative tmp cache dir that resolves to an absolute path. In any checkout whose path has a dot, such as a worktree under .claude/worktrees/ or a .workflow directory, 16 of the 23 tests fail. CI's checkout path has no dot, so CI never sees it.
• Users: a cache dir like /home/app/.sentry or /opt/my.app/cache logs "Disabling profiling because traces directory path contains invalid character: .". Because init() returned true on every call after the first, only the first start was refused, so users lose the first profile chunk and see a misleading warning.

Cause

The blocklist was added in b065ef1 ("re-add asyncprofiler classes, cr changes", #4556), about an hour after Seer flagged the async-profiler command string as a possible injection risk. It reads like a list of shell metacharacters, but no shell runs the command. async-profiler 4.4's Arguments::parse treats only two characters in the path specially:

• , separates arguments (start,jfr,...,file=<path>);
• % starts a file-name pattern (%p, %t, %n{MAX}, %{ENV}).

It splits key=value at the first =, so = is safe too.

Fix

#6334 rejects only , and %, and makes a rejected config stay rejected, as AndroidContinuousProfiler does.