Split from (#1 was done)
*2. If a locale has a macroregion (eg 001, 419, 150), we may want to treat them differently.*
It is clear that 419 is substantially different from any of its sublocales, and purposefully so. And in user interfaces it is treated as a separate animal. So I think we want to treat that like #1.
Error: (TestBasic.java:781) Locale has children but is missing default contents locale: es_419, children: [es_BO, es_BR, es_BZ, es_CL, es_CO, es_CR, es_CU, es_DO, es_EC, es_GT, es_HN, es_MX, es_NI, es_PA, es_PE, es_PR, es_PY, es_SV, es_US, es_UY, es_VE|es_AR,]; fyi, empty children: 
I'm less sure about the English cases, which are "fake" locales for our convenience in managing data, and I'm not sure that people really surface them in UIs (or should). Especially en-150, which is very thinly populated. The simplest thing to do would be also to treat them like #1 for the purpose of the test, but we may want to add some information that tells implementers that these are special.
Error: (TestBasic.java:781) Locale has children but is missing default contents locale: en_001, children: [en_AG, en_AI, en_AU, en_BB, en_BE, en_BM, en_BS, en_BW, en_BZ, en_CA, en_CC, en_CK, en_CM, en_CX, en_CY, en_DG, en_DM, en_ER, en_FJ, en_FK, en_FM, en_GB, en_GD, en_GG, en_GH, en_GI, en_GM, en_GY, en_HK, en_IE, en_IL, en_IM, en_IN, en_IO, en_JE, en_JM, en_KE, en_KI, en_KN, en_KY, en_LC, en_LR, en_LS, en_MG, en_MO, en_MS, en_MT, en_MU, en_MW, en_MY, en_NA, en_NF, en_NG, en_NR, en_NU, en_NZ, en_PG, en_PH, en_PK, en_PN, en_PW, en_RW, en_SB, en_SC, en_SD, en_SG, en_SH, en_SL, en_SS, en_SX, en_SZ, en_TC, en_TK, en_TO, en_TT, en_TV, en_TZ, en_UG, en_VC, en_VG, en_VU, en_WS, en_ZA, en_ZM, en_ZW|en_150,]; fyi, empty children: 
Error: (TestBasic.java:781) Locale has children but is missing default contents locale: en_150, children: [en_CH, en_DE, en_DK, en_FI, en_NL, en_SE, en_SI|en_AT,]; fyi, empty children: