test: make e2e "singleCommandTimeout" configurable for azs

[haofan-ms]

Reason for Change:

Make "singleCommandTimeout" param in e2e configurable for AzureStack, as this is causing timeout in test failures.

Issue Fixed:

Credit Where Due:

Does this change contain code from or inspired by another project?

• No
• Yes

If "Yes," did you notify that project's maintainers and provide attribution?

• No
• Yes

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

[codecov]

Codecov Report

Merging #4372 (6d531fd) into master (60828c7) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #4372   +/-   ##
=======================================
  Coverage   72.04%   72.04%           
=======================================
  Files         141      141           
  Lines       21631    21631           
=======================================
  Hits        15584    15584           
  Misses       5096     5096           
  Partials      951      951           

Impacted Files	Coverage Δ
pkg/engine/templates_generated.go	43.31% <ø> (ø)

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[jadarsie]

/lgtm

[acs-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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