The work in getExecutablesInPath is done many times before caching happens

[Tyriar]

One of the reasons for #256746 might be that we don't respect the cancelation token. When I add a few logs, I see a lot of _getExecutablesInPath calls going the non-cached route just by typing in the terminal:

These a, b logs should never have happened.

The fetchAndCacheShellGlobals change we did in #259051 also needs to happen for getExecutablesInPath.

[Tyriar]

Also it's happening twice in parallel here:

vscode/extensions/terminal-suggest/src/terminalSuggestMain.ts

Lines 254 to 262 in 264d466

	const [commandsInPath, shellGlobals] = await Promise.all([
	pathExecutableCache.getExecutablesInPath(terminal.shellIntegration?.env?.value, terminalShellType),
	(async () => {
	const executables = await pathExecutableCache.getExecutablesInPath(terminal.shellIntegration?.env?.value, terminalShellType);
	return getShellGlobals(terminalShellType, executables?.labels, machineId, remoteAuthority);
	})()
	]);
	const shellGlobalsArr = shellGlobals ?? [];