Fix test skip mechanism to handle empty env vars

[geropl]

Description

Fixes the ifEnvVarNotSet utility to properly skip tests when environment variables are set to empty strings.

Problem

The test skip mechanism was failing in CI because:

1. ifEnvVarNotSet only checked for undefined
2. In CI, Bitbucket token env vars were set to empty strings ("")
3. Empty string ≠ undefined, so tests ran without valid tokens
4. Tests failed with 401 authentication errors

Example from CI logs:

GITPOD_TEST_TOKEN_GITHUB: ***          ← Has value (tests pass)
GITPOD_TEST_TOKEN_GITLAB: ***          ← Has value (tests pass)
GITPOD_TEST_TOKEN_BITBUCKET:           ← Empty string (tests fail!)
GITPOD_TEST_TOKEN_BITBUCKET_SERVER:    ← Empty string (tests fail!)

Solution

Updated ifEnvVarNotSet to check for both undefined and empty strings:

const value = process.env[name];
const skip = value === undefined || value === '';

This ensures tests are skipped when tokens are missing or empty, preventing spurious CI failures.

Testing

Verified the logic handles all cases correctly:

• undefined → skip
• Empty string → skip
• Has value → don't skip

Related

Fixes test failures seen in https://github.com/gitpod-io/gitpod/actions/runs/20091345213/job/57639328696

[github-actions]

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